Cartouche for joining metal bodies, especially for light metals, by welding



@fit 3951 A. SCHRLTKNECHT 5 CARTOUCHE FOR JOINING METALBODIES,-ESPECIALLY FOR LIGHT METALS, BY WELDING Original Filed Dec. 8,1943 QIIIIIIIII/IIIIIIIIIIII fiweizz on- ,JCAM

aienteoi Oct. 2, 1951 INING METAL BODIES, LIGHT METALS, BY

CARTOUCHE FOR J ESPECIALLY FOR WELDING Adolf schilt nfi l Neuhausen,

Switzerland, as-

signor to Societe Anonyme pour IIndustrie de lAlumluium, Chippis,Switzerland Original application December 8, 1943, Serial No. 513,442.Divided and this application October 2, 1946, Serial No. 700,809. InSwitzerland September 30,1942

Section ll, Public Law 690, August 8, 1946 Patent expires September 30,1962 The present invention relates to a .cartouch for carrying out a.welding process in which a mixture of exothermic reaction serves as thesource of heat. j

This application is a division of my prior application Serial No.513,442, filed ,December 8', 1943, now abondoned.

Processes of this kind are known under the trade name Thermit welding.They are used, for instance. for the welding of abutting rail ends to bejoined. The rail ends are surrounded by a mould, into which one pours aThermit mass which is allowed to react. The molten iron eiiectuates thewelded joint, whereas the slag composed principally of aluminium oxidecollects in the upper part of the mould. Of course, this method is onlyapplicable to the joining "of iron bodies, as the 'I'hermit masssupplies molten iron. It cannot be applied to other metals, especiallynot to light metals.

It is also known to butt-weld iron tubes by pouring liquid Thermit masson the abutting ends and subsequently upsetting; in such case' the slagflows round the abutting ends and forms a casing, whereafter the iron ofthe Thermit mixture solidifies around the slag, so that it is finallypossible to remove the iron.

It is an object of the present invention to provide an improved weldingcartridgefor autogenously joining non-ferrous metal bodies by a weldingmethod which is particularly suitable for butt-welding of aluminium oraluminum alloy rods, extruded sections, tubes and cables and whichconsists of surrounding the parts to be joined by an alumino-thermic orlike exothermic reaction mass, igniting said mass to cause the reactionto take place and retaining the molten products produced by the reactionmass within said mass and excluding said mass from direct contact withthe welding, the necessary heat for melting the ends of the metal bodiesto be joined by welding being supplied by the exothermic mass. Workingpieces of other metals, for example of magnesium, brass and so on. canalso be welded by means of the cartouch according to the invention. Onemay also join together difierent metals, such as copper with aluminum,taking care that more heat be supplied to the metal having the highermelting point.

The invention consists essentially in providing a cartouch comprising anouter cover, an inner cover having a cross section substantiallyconforming to the cross-section of the metal bodies to be welded, and anexothermic reaction mass enclosed between said outer and inner covers.

12 Claims. (Cl. 126-263) The welding process carried out by means of theimproved cartouch consists in bringing together the parts to be joinedwithin the cartouch so that they will be surrounded by the saidexothermic reaction mass, and then letting the reaction take place,whereby no molten products escape from the reacting mass and thenecessary heat for welding is supplied by the exothermic mass. Asdistinguished from the known method of Thermit welding of steel, themetal produced by the exothermic reaction of the above process is notused by the weld, but only the heat supplied by the reaction.

It is not in all cases necessary that the parts brought together toucheach other prior to the reaction. In particular a contact is unnecessarywhen the parts to be joined are pressed together after beginning ofmelting.

This upsetting after beginning of melting is the best practice, as it isthe surest warrant for a good welding joint. It is of course possible toinsert a small piece of metal (or several pieces) between the parts tobe joined, which piece also melts. If such a piece is introduced onlyafter beginning of melting of the parts to be joined, it is possible toupset them by means of the inserted piece, this being particularlyadvantageous when the parts to be joined cannot be pressed one. againstthe other, for example in the case of bus-bars. It, is also possible toplace the metal piece near the abutting ends in tight contact with theexothermic mixture, so that it melts and flows between the parts to bejoined.

In carrying out the process, care must be taken that the metal which isproduced by the reaction of the exothermic mixture does not disturb thewelding. This metal (which in practice is always iron) must remain inthe reacting mixture and prevented from running out. For this purposesubstances which retain the metal formed may be added to the reactionmixture. Such a substance is first of all magnesium oxide. An excess ofiron oxides can also be used. The most suitable way however is to choosethe reacting substances so that they furnish themselves a slag capableof retaining the metal formed. This can be attained for instance with amixture of magnesium, alumium and oxides of iron, the amount ofmagnesium being much greater than the amount of aluminum. A suitablemixture is composed, for example, of 20 to 30% Mg, to 7% A1 and 67 to78% mill scale. Good results have been obtained with a mixture of 24 to26% Mg, 3 to 5% Al and 69 to 73% mill scale. A mixture of pure magnesiumThermit with an amount of iron oxides in excess of that required forcompletely oxidizing the magnesium has also proved One has to avoid atoo violent as well as a too slow reaction.

The reaction is started in known manner, prefterably by means of anigniting mixture, consisting for instance of potassium chlorate,aluminum powder, magnesium powder and sulphur.

In particular with the butt-welding of elongated bodies of light metalsit is advantageous to surround the ends to be joined with a tube roundwhich the reaction mass is disposed, preferably in briquetted form. Inthe welding of alminum the tube can be made of aluminum. The tube meltstogether with the ends to be joined and can furnish a part of the metalfor the weld. A tube made from ceramic material is also utilizable, butsomewhat less advantageous. It is generally desirable, for instance inthe buttwelding of electrical cables of aluminum, that the weld does nothave a substantially greater diameter than the cable itself. In case ofnecessity, metal in excess must be removed from the joint, suitably byfiling or by abrasive means. When working without a tube surrounding theends to be joined it is practically impossible to prevent the diameterof the weld from becoming greater than the diameter of the joined parts.For the purpose of preventing a too great diam eter of the weld or ofgiving to the weld a predetermined shape, it is suitable to push on theends to be joined a tube made from a substantially higher melting metal,for instance with aluminum an iron tube, which tube serves as mould andis provided with a longitudinal notch which can be easily opened afterthe welding operation and the removal of the reacted heating mixture.When it is not a question of buttwelding elongated bodies with a simplecrosssection such as rods, cables and tubes, but of cross-sections ofother shapes such as T-girders, obviously one should take anothersuitable mould-like casing instead of a tube.

If tubes or hollow cables, for instance of aluminum, are to bebutt-welded so that the hole must remain uninterrupted, one inserts asecond tube into the ends to be joined.

The accompanying drawings illustrate two forms of a cartouch accordingto the present in-- vention.

In the drawings:

Fig. 1 is a longitudinal sectional view of the ends of two aluminumcables to be butt-welded and of the surrounding cartouch of exothermicreacting mixture.

Fig. 2 is a cross section along the line II-II of Fig. 1.

Fig. 3 is a longitudinal section of a slightly modified cartouch.

Fig. 4 is a cross-section along line IVIV in i 3.

Fig. 5 is a cross-section similar to Fig. 4.

In the accompanying drawings the numerals I and 2 designate the ends ofa cable which are introduced into a cylindrical hollow cartouch(briquette) 3. This cartouch is provided with an inner iron tube 6,which keeps the metal produced in the reaction mass off the joint andhinders a substantial enlargement of the diameter at the weld. 5 is'alongitudinal fold which facilitates the removal of the iron tube afterexecution of the welding. 8 is an inserted ring of aluminum which actsas an abutment and serves to exactly center the weld. I is a reactionmass composed of magnesium, aluminum and mill scale and compressed underhigh pressure. 8 designates an igniting mixture, which can be ignited bymeans of the tearing-off strip '9, where pon the reaction of the Thermitmass start I0 is a tube of cardboard provided with two end covers I Ifor enclosing the reaction mass.

The arrows show the direction of the upsetting pressure.

For security of storage and transportation it is suitable to protect thetearing-off strips and the cartouch by a casing, which protects them atthe same time against entrance of moisture. The interstices into whichmoisture could penetrate may be sealed by means of paramn.

The cartouch illustrated in Figs. 3-5 differs from that described aboveinasmuch as the inner iron tube is made in two halves 4' and 4" havingabutting flanges l2. Two bars l3 of U- shaped cross-section are placedto embrace the flanges I2 for holding the two halves l and 6" together,which bars can easily be removed after the welding. Instead of thetearing-ignitionstrip 9 the ignition is eflected by means of the head ofspecially prepared matches (Bengal fire matches) It inserted in holesl5. During the transport of the cartouch plugs, for instance rivets l6,are inserted in the holes l5 so that there is no danger of prematureignition of the cartouch.

It has already been pointed out that the safest joint is obtained whenthe ends are upset one against the other after they begin to melt. Forthis purpose one uses advantageously an upsetting device provided withtwo sets of jaws between which the ends to be welded are clamped andwhich, before the ignition of the reaction mixture, are submitted tospring pressure tending to approach the clamps and thereby the ends oneagainst the other. As soon as the parts to bejoined begin to melt, anautomatic upsetting through the sets of jaws takes place. The upsettingdevice can be made so light that it can be, for instance, suspended onoverhead transmission cables of aluminum for the purpose of weldingthem.

The cartouch according to the invention can also be used for thesimultaneous welding of more than two bodies. One can also make T-likejoints, for example branchings on electrical conductors.

As compared with known welding methods the process using the cartouchaccording to the invention presents very important advantages. It is notnecessary, as with other Thermit welding methods, to have at onesdisposal a little foundry equipment. An exceptionally important field ofapplication is the welding of electrical conductors in the open country,especially of high-tension overhead transmission lines, as it, issuflicient to carry a handy upsetting device and the necessary-number ofcartouches.

When the welding must be carried out on the line already suspended onthe mast, any other method is hardly applicable.

The cartouch according to the invention moreover allows the joining ofbodies of relatively thick cross-section, on which the electricbuttwelding would only be possible with extremely powerful machines andthe gas welding could no more be applied.

The cartouch can be used by a non-skilled worker.

I claim:

1. A welding cartridge for autogenously welding non-ferrous metalbodies, comprising an inner tubular cover member adapted to closely fitto and surround the metal bodies near the surfaces to be united, anouter tubular cover member surrounding said inner tubular member inspaced relation thereto, an exothermic reaction mass enclosed in thespace between said inner and outer tubular members, an igniting mixturealso enclosed in the space between said tubular members, and atearing-off strip partly embedded in the igniting mixture, saidtearing-oil strip pro ecting out of said outer tubular member andadapted to be gripped for being torn off to ignite said mixture.

2. A welding cartridge for autogenously welding non-ferrous metalbodies, comprising an inner tubular cover member adapted to closely fitto and surround the metal bodies near the surfaces to be united, anouter tubular cover member surrounding said inner tubular member inspaced relation thereto, an exothermic reaction mass enclosed in thespace between said inner and outer tubular members, and an ignitingmixture also disposed in the space between said inner and outer tubularmembers, said outer tubular cover member and said igniting mixture beingprovided with registering apertures adapted to either receive anignition match for initiating reaction or a safety plug during transportof the cartridge.

3. A welding cartridge as claimed in claim 2 in which said inner tubularcover member consists of iron.

4. A welding cartridge for autogenously welding non-ferrous metalbodies, comprising an inner tubular cover member adapted to closely fitto and surround the metal bodies near the surfaces to be united, saidinner tubular member consisting of iron and having its interior surfacecoated with a substance preventing alloying between iron and aluminum,an outer tubular cover member surrounding said inner tubular member inspaced relation thereto, an exothermic reaction mass enclosed betweensaid outer and inner tubular members, and an igniting mixture alsoenclosed between said tubular members, said outer tubular member and theigniting mixture being provided with registering apertures adapted toeither receive an ignition match for initiating reaction or a safetyplug during transport of the cartridge.

5. A welding cartridge for autogenously welding non-ferrous metal bodiescomprising an inner tubular cover member adapted to closely fit to andsurrounding the metal bodies near the surfaces to be united, an outertubular cover member surrounding said inner tubular member in spacedrelation thereto, and an exothermic reaction mass composed of finelydivided magnesium, aluminum and oxides of iron enclosed between saidinner and outer tubular members.

6. A welding cartridge as claimed in claim 5, wherein said exothermicmass is composed of 20-30% magnesium, 2-'7% aluminum and '1- 78% millscale.

'7. A welding cartridge as claimed in claim 5, wherein said exothermicreaction mass is composed of 24-26% magnesium, 35% aluminum and 69-73%mill scale.

8. A welding cartridge as claimed in claim 5, wherein said exothermicreaction mass is composed of magnesium Thermit with an amount of ironoxides in excess of that required for completely oxydizing themagnesium.

9. A welding cartridge as claimed in claim 1, in which said outer andinner tubular members are of cylindrical shape, said inner tubularmember being open at both ends to permit insertion of the ends of themetal bodies to be welded from both sides of the tubular member.

10. A welding cartridge for autogenously welding non-ferrous metalbodies, comprising an inner tubular cover member adapted to closely fitto and surround the metal bodies near the surfaces to be united, anouter tubular cover member surrounding said inner tubular member inspaced relation thereto, an exothermic reaction mass enclosed betweensaid two tubular members, and abutment means disposed within said innertubular member to provide for centering of the weld.

11. A welding cartridge as claimed in claim 1, in which said inner andouter tubular members are formed by concentrically disposed tubes.

12. A welding cartridge for autogenously welding non-ferrous metalbodies comprising an inner tubular cover member adapted to closely fitto and surrounding the metal bodies near the surfaces to be united, anouter tubular cover member surrounding said inner tubular member inspaced relation thereto, an exothermic reaction mass composed of finelydivided magnesium, aluminum and oxides of irons enclosed between saidinner and outer tubular members, an igniting mixture also enclosed inthe space between said tubular members, and a tearing-off strip partlyembedded in the igniting mixture, said tearing-01f strip projecting outof said outer tubular member and adapted to be gripped for being torn011 to ignite said mixture.

ADOLPH SCHILTKNECHT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 412,187 Jeffery Oct. 1, 1889648,475 White May 1, 1900 778,117 Culin Dec. 20, 1904 802,256 Bambergeret al. Oct. 17, 1905 847,668 Lang Mar. 19, 1907 934,711 Chapman Sept 21,1909 1,246,909 Schmidt Nov. 20, 1917 1,417,075 LaCour May 23, 19221,838,357 Bottrill Dec. 29. 1931 2,212,441 Katz Aug. 20, 1940 2,265,172Katz Dec. 9, 1941 2,388,466 Galdwell Nov. 6, 1945 FOREIGN PATENTS NumberCountry Date 248,020 Germany June 14, 1912

